Natural Selection exam Flashcards
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Natural Selection
A key mechanism of evolution where certain traits enhance survival and reproduction, leading to evolutionary changes in populations over time.Observation 1 of Natural Selection
Variation is inherited; not all organisms in a population are identical, and much of this variation is passed from parent to offspring.Observation 2 of Natural Selection
Species tend to overproduce offspring, more than the environment can support.Inference 1 from Natural Selection Observations
Certain traits will make survival and reproduction more likely, while others will make them less likely.Inference 2 from Natural Selection Observations
Traits that help organisms survive and reproduce will accumulate in the population, leading to evolution.Example of Natural Selection
Snowshoe hares with coat color variation; white hares are less camouflaged in areas with little snow, leading to higher predation rates.Adaptation
A trait that increases an organism's fitness in a particular environment.Fitness
The likelihood that an organism is able to survive and reproduce.Relative Fitness
Fitness measured in comparison to other organisms in the population.Absolute Fitness
The total number of offspring an organism produces.Does natural selection introduce variation?
No, natural selection selects from existing variation in the population.What is required for natural selection to occur?
Existing variation within the population.How does the environment affect fitness?
Fitness depends on the environment; traits that are advantageous in one environment may not be in another.Population Evolution
Populations evolve over time as the frequency of advantageous traits increases.Do individuals evolve?
No, individuals do not evolve; populations do.How does natural selection affect populations over time?
It increases the number of adaptations to the current environment.What happens if the environment changes?
The population will evolve as different traits become advantageous.Overproduction
The production of more offspring than the environment can support.Variation
Differences in traits among individuals in a population.Camouflage
An adaptation that allows organisms to blend in with their surroundings.Example of Overproduction
Female snowshoe hares can birth 12+ offspring per year, but not all survive.What is the role of competition in natural selection?
Members of the same species compete for resources, affecting which traits are passed on.Probability in Natural Selection
Survival and reproduction are based on probability; advantageous traits increase the likelihood of survival.How does natural selection shape populations?
It increases the frequency of advantageous traits, making populations better fit their habitats.Darwin's 4 Postulates
Variation, inheritance, overproduction, and differential survival and reproduction.Genetic Variation
Differences in DNA among individuals, leading to variation in traits.What is an example of a trait affected by natural selection?
Coat color in snowshoe hares, which affects their camouflage and survival rates.How does natural selection lead to evolution?
By increasing the frequency of traits that enhance survival and reproduction in a population.What is the ultimate result of natural selection?
Populations become better adapted to their environments over time.